1. Field of the Invention
The present invention relates to a press apparatus. More specifically, the present invention relates to a press apparatus which makes it easy to remove a passive cam from the a lower die so as to improve workability. Moreover, the present invention relates to a press apparatus which is constituted so that a guide post is mounted across the nearest vicinity of a portion of the passive cam to which a processing member such as a punch is mounted, and is positioned on both sides of the processing member, and which can improve processing accuracy of a cam die as much as possible.
2. Description of the Background Art
A normal press apparatus is constituted so that a lower die is mounted to a bed of a press machine and a an upper die is mounted to a ram, and when the upper die is lifted and lowered, boring and forming processes are performed. Since the upper die is lifted and lowered in the vertical direction, the process in the lateral direction is performed in such a manner that the processing force in the vertical direction is converted into the processing force in the lateral direction by using a cam member.
The description will be given as to an example where a hole is bored in a side wall of a work by using the press apparatus having the cam member.
As shown in FIGS. 6 and 7, a locating member 104 for locating a work 103 is projected from a lower die 101. A passive cam 107 having a punch 106 is provided on a position which faces a blanked hole 105 in a side wall of the work 103 so as to slide. A heel 108 is fixed to a rear portion of the passive cam 107. A coil spring 109 is fitted into the passive cam 107 so as to be externally fitted in a point of a rod 110 through which the heel 108 is put. One end of the coil spring 109 is brought into contact with the heel 108, and a nut 112 is fitted to the other end of the coil spring 109 via a washer 111. As a result, the coil spring 109 pulls the passive cam 107 in which the hole was provided back to the work 103. An actuation cam 118 is projected from the upper die 116 so as to be in a position which faces the passive cam 107.
The upper die 116 is lowered and the actuation cam 118 advances the passive cam 107 against the applied force of the coil spring 109, and a hole 105 is bored into the work 103 by the punch 106 and a die 125. When the upper die 116 is lifted, the passive cam 107 is brought back by the applied force of the coil spring 109.
Since the hole is bored in the side wall of the work 103, as mentioned above, the passive cam 107 having the punch 106 approaches and separates from the work 103 so as to slide on the lower die 101. Since the hole is bored by the punch 106 and the die 125, the passive cam 107 must slide exactly. A flange 121 is projected from both sides of the lower part of the passive cam 107, and a sidewise guide plate 122 and an upper guide plate 123 for guiding the flange 121 are fixed to the lower die 101. A reference numeral 124 is a wear plate.
Since a processing member such as the punch 106 is mounted to the passive cam 107, there occasionally arises a problem that a cutting edge of the punch 106 is nicked during the processing and thus it should be repaired. In the mounted state shown in FIG. 7, since the repair is impossible, the passive cam 107 should be removed from the lower die 101. The heel 108 is removed and the passive cam 107 is guided by the sidewise guide plate 122 and the upper guide plate 123 so as to be moved towards the opposite-work side (backward). Thereafter, the passive cam 107 is passed through the sidewise guide plate 122 and the upper guide plate 123 so as to be removed from the lower die 101. Therefore, it takes a long time to remove the passive cam 107 from the lower die 101, and thus repairing workability is not good.
In addition, while the passive cam 107 slides repeatedly, it is worn out, and thus a gap is generated between the passive cam 107 and the sidewise guide plate 122. As a result, the passive cam 107 cannot slide in the straight linear direction, and it slides non-linearly due to the gap. Since the punch 106 mounted to the passive cam 107 also slide non-linearly, the punch 106 cannot blank the die 125 in its whole periphery with a suitable clearance. As a result, burr occurs on the periphery of the blanked hole, and a high-quality boring process cannot be performed. Moreover, since the punch 106 and the die 125 carried out the blanking with burr, the gap causes the cutting edges of the punch 106 and the die 125 to be nicked. In order to attain the high-quality pressing process, the passive cam 107 should be moved straight and exactly without non-linear movement.
Further, since inclined weight due to the forming process is placed on the passive cam, the passive cam is apt to shift. Therefore, this shift is eliminated, and thus a product should be processed into a desired shape.
Furthermore, it is necessary to improve processing accuracy of a cam die as much as possible.